Convergence Insufficiency: this common near vision disorder can cause suppression in one eye, but because the suppression is occasional (intermittent) and/or might alternate between one eye and then, the other, it rarely leads to a true lazy eye condition (Amblyopia).
Common Causes of Lazy Eye: Strabismus, Anismetropia, Blockage of Eye
The most common causes of amblyopia are constant strabismus (constant turn of one eye in any direction, but an inward turn or crossed eyes is much more common),
Anisometropia (differences in vision and/or prescription between the two eyes) which leads to anismetropic amblyopia or refractive amblyopia, and/or physical blockage
of an eye due to cataract, trauma, lid droop (ptosis), blocked tear duct, etc. Other less common causes are reported to be congenital disorders and vitamin A deficiency.
Symptoms of Lazy Eye in Children - Detection
and Diagnosis of Lazy Eye
Since amblyopia usually occurs in one eye only AND a lazy eye condition can exist without a noticable eye turn, many parents and children
are not aware of any symptoms. In other words, unfortunately, symptoms of lazy eye are often NOT obvious to the outside observer (parent, teacher, school nurse or pediatrician, etc.).
An eye exam by a pediatrician or the 20/20 eye chart screening simply is not
adequate for the detection of amblyopia (and other early childhood visual conditions). The most important diagnostic tools are the special visual acuity tests other than the 20/20 eye test charts currently used by schools and pediatricians.
and general eye doctors. Examination with cycloplegic drops can be necessary to
detect this condition in young children.
vision evaluations are highly recommended for infants and pre-school children. Otherwise, many children go undiagnosed until they
have their eyes examined at the eye doctor's office at a much later age.
Lazy Eye Treatment - How to Correct a Lazy Eye
Neuroscience has proven that the human brain can change at any age (neuroplasticity), so lazy eye is treatable at any age, too. Treatment involves glasses, atropine drops, eye patching, and/or vision
therapy, which includes eye exercises, visual-motor processing activities and neurological therapies. Medical research has proven that lazy eye
is successfully treated up to the age of 17 with therapies. See National
Institutes of Health -- National Eye Institute; Older Children Can Benefit
From Treatment; Lazy Eye.
To quote Dr. Leonard J. Press, FAAO, FCOVD: "
Treatment of amblyopia after the age of 17 is not dependent upon age,
but requires more effort including vision therapy.
been proven that a motivated adult with strabismus and/or amblyopia
who works diligently at vision therapy can obtain meaningful improvement
in visual function. As my adult patients are fond of saying: "I'm not looking
for perfection; I'm looking for you to help me make it better". It's
important that eye doctors don't make sweeping value judgments for patients.
Rather than saying "nothing can be done", the proper advice would be:
"You won't have as much improvement as you would have had at a younger
age; but I'll refer you to a vision specialist who can help you if you're
Every amblyopic patient deserves an attempt at treatment.
are possible at any age with proper treatment, early detection and treatment
still offer the best outcome. Nevertheless, a desire for treatment at an early age should not motivate a rush to lazy eye surgery. When considering treatment options, it is important to understand that lazy eye results from problems in the brain (neurological deficit) and surgery commonly done for lazy eye is performed on the muscles on the outside of the eye(s) only. In many cases, lazy eye surgery will provide cosmetic benefits only and does not improve the patient's vision. Treatment options that are directed specifically toward vision improvement should be exhausted before eye muscle surgery is considered.
Eye (Amblyopia) and Crossed Eyes (Strabismus) are not the same condition.
Many people make the mistake of saying that a person who has a crossed
or turned eye has a "lazy eye," but amblyopia and strabismus
are not the same condition. Some of the confusion may be due to the fact
that an eye turn can cause lazy eye. In other words, amblyopia can result from a constant
unilateral strabismus (i.e., an eye that turns or deviates all of the
time). Alternating or intermittent strabismus (an eye turn which occurs
only some of the time) rarely causes amblyopia.
While a deviating eye (strabismus) can be easily spotted by the layman,
amblyopia without strabismus or associated with a small deviation usually
can be not noticed by either you or your pediatrician. Only an eye doctor
comfortable in examining young children and infants can detect this type
of amblyopia. This is why early infant and pre-school eye examinations
are so necessary.
Due to misunderstanding or misuse of the terms for different visual conditions
(i.e., deviating eyes vs. lazy eye), many people are inaccurately labelled
as having a "lazy eye." If you think you or someone you know has lazy
eye, learn more at Constant
or Intermittent?, What
is Convergence Insufficiency?, What
is Double Vision?, What is Strabismus?,
Convergence Insufficiency is a fairly common visual condition which is
also (1) confused with lazy eye; (2) not easily discernable to the observer
and (3) not detected by the standard 20/20 eye test. Convergence Insufficiency
is estimated to affect 5 out of 100 children and adults. See What
is Convergence Insufficiency?
See References to Peer-Reviewed Research and Scientific Studies on Lazy Eye or Amblyopia Treatment